The head of the world's biggest food and drink company says using crops like wheat and corn to make biofuels is putting world food supplies in peril.

The chairman and chief executive of Nestle, Peter Brabeck-Letmathe, says there'll be nothing left to eat if 20 per cent of the world's oil demand is fulfilled by biofuels, as predicted.

He says it's morally unacceptable and irresponsible to grant enormous subsidies to bio-energy.

Mr Brabeck-Letmathe says water, and land for cultivation, are becoming rarer, while biofuel demand is driving up the price of maize, soya beans and wheat.